Reheater for steam-turbine installations



Dec. 7 1926.

1,610,034 A. w. BOWERBANK V- -REHEATER FOR STEAM TURBINE INSTALLATIEONS Fuedoct. 11, 1920 4 sheets-sheet v1 A. w. BOWERBANK A REHEATER FOR STEAM TURBINE INSTALLATIONS Filed Oct. 11. 1920 4 Sheets-Sheet `a A. W. BOWERBANK REHEATER FOR STEAM TURBINE INSTALLATIONS Filed Qt 11, 1920 4 Sheets-Sheet 3 Dec. 7 1926. 1,610,034

A. w. Bowi-:RBANK REHEATER FOR vSTEAM TURBINE INSTALLATIONS Filed 001'.. ll, 1920 4 Sheets-Sheet 4 Fatentecl Dec. 7, 1926.

UNITED STATES PATENT QFFltF..

ALBERT WLLAVI BOYVERBANK, OF NECASTLE-UE'ON-TYNE, ENGLAND, ASSIGNGR,

BY MESNE ASSIGNMENTS, '.O ELECTRICAL MPRVEIVIENTS LZ'NTED, OF NEW- CASTLE-UPON-TYNE, ENGLANB.

REHEATER FOR STEAl'I-T'URBINE INSTALLATIONS.

Application filed Getober 11, 1820, Serial No. 416.302, and in Great Eritain December 22, 1919.

rlhis invention is for improvements in or relating to 1re-heaters for steam turbine installations and has for its object to provide means whereby the heating of the re-heater can be regulated in accordance with the amount of steam passing through it.

According to the present invention a regulating device for a re-heater of a multiplecipansion turbine comprises in combination heating means for the re-heater, a regulator for said heating means, and means to control the operation of the regulator proportionately or substantially proportionately with the turbine-load. By controlling the regulator in this manner the purpose of the invention is obtained, that is to sav the reheater will be heated approximately -in accordance with the amount of steam which it has to treat at any one time.

Conveniently, the regulator is a pressurecontrolled device operated by the pressure of the steam 'passing to or from the reheater, for example, by taking a small quantity of the steam from a suit-able point on the turbine, or from the re-heater, or the inter-connecting pipes between the re-heater and the turbine to operate said pressure device. rThe regulation of the heat for the re-heater can be eifected by controlling the supply of fuel and air, or fuel only, to fluidfuel burners or burners of a similar character adapted to use other comminuted or flowable fuels. A

In a preferred form of the invention, a plurality of fuel burners are employed as a means to tire the re-heater and theyare combined with a fuel-control device and means operatively connecting` the device with the regulator.

A feature of the invention comprises a fuel-control valve or the like for each burner and a sliding member operatively connectedV with the regulator and with each of the control-valves characterized by the said sliding member being so arranged as to operate, during a follow-through movement, to close or open in succession the valves controlling tie supply of fue-l to the burners as the pressure falls or rises respectively. The burners can conveniently be of the type for burning liquid fuel such as heavy hydrocarbons.

A further feature of the invention comprises a pressure-regulator in the form of av piston-device in which steam is admitted to one face of the piston and spring pressure is applied to the other face in opposition to the steam-pressure.

One preferred form of the invention will now be described in detail by way of example only, with the aid of the accompanying drawings, in which I Figure 1 is an illustration in front elevation, largelydiagrammatic, of one form of the apparatus according to the present invention, and is a partial section on the line 1 1 of Figure 2,

Figure 2 a section on the line 2 2 of As shown in Figure 1, the. high-pressure section of the turbine 6 is connected by means of a conduit 7 with the lower end of a re-heating chamber 10. The low-pressure section 8 of the turbine is also connected with the re-heating chamber at upper end by means of a conduit 9. i

In the form illustrated, the rc-beater consists of a chamber 10 in which are disposed four banks of horizontal tubes 11, 12,' 13 and 14taround and over which heated gases are caused to circulate.4 To aid in the circulation, batlies 15 are providedso that the gases have to pass over the tubes in the direction of the arrows shown in Figure The hot gases are ther carried by means of trunk 16 through a series of vertically-disposed tubes 17 contained in a casing 1S in the.V

chamber 10. rlhe gases pass from the truuk 16l downwardly through the upper ends of the tubes 17 and are exhaustedl through the lower ends of theftubes to a trunk 19 communicating with Steam admitted through the conduit 7 passesinto headers 2O for the banks ot tubes 12 and 14, through those tubes, headers 21, thence by Way ot conduits 22 to headers 23 for the banks of tubes ll and 13, and finally passes through head-ers 24 to the outletconduit 9.

The gases tor heating the chamber l0 are obtained with the aid ot -tuel burners 25 arranged in a flue 26 below the level `ot the chamber l() and communicating with the back end thereot through an opening 2'?. 1n the example illustrated, four burners are provided and the air-supply to them is conveniently heated by admitting air to the casing 18 through an inlet-port 51 at its lov-:er end and extracting it from the casing and passing it to the burners through air-conduits 28. The air as it passes through the casing is heated by the gases which pass downwardly through the tubes 17. 1n front ot the burners 25 there is preferably a perforated distributing baille 29, and between the bafile 29 and the outlet 27 a feed-Water heater 30 may conveniently be placed.

1n order to regulate the heat supplied by the burners in accordance With the quantity ot steam passing from time to time through the re-heating tubes, the following means is adopted: Suitable fuel such as gas or oil is admitted to the upper part of each regulating valve body trom a main supply conduit bl, see Figures 3 and 4, from which it passes to each burner through a spring-loaded mushroom valve 32. 1n the Jform shown, the stein o1 each valve extends through the upper part ot the valve body, and is combined with a spring 33 normally tending to keep the valve on its seat. The upper extremity of each valve-stem terminates in an anti-friction roller 34.

Supported above all the valve-stems is a sliding bar 35 carried in bearings 36 conveniently formed in the upper eXXtremities of arms branching out and cast integral with the upper part ot the regulating valve body. The bar is formed with a number ot' downwardly-projecting cam-surfaces 37, one for each valve-stein, and these project-ions are so disposed on the bar that an endvvise movement of the latter towards the right in Figure 3 Will bring the projections successively into engagement with the anti-triction rollers ot the several valves so that the valve-Steins are depressed, one atter the other, thereby opening the valves and admitting fuel to the several burners. The cams 37 are Ot such length in their direction of movement that during the successive depression of the valve-stems, those lirst depressed Will remain so during that tull movement of the rod 35 which causes the opening oit' the valves.

The means tor controlling movement of the rod 35 comprises a bell-crank lever 38 pivoted at in -i extension from one ot "gulating vai'fe bodies, and connected tree ends to the rod 235 and a pistonl fi L' w, fm1 A d 4t), respectively. n extends i. e latter from a pieton 4l Working in a vertical cylinder 42 supplied with steam from the turbine through a steam-inlet 43 -which admits steam to the upper tace of the piston. Between the lower tace or the piston and the louer end oi' the cylinder is a spring 44 tending normally to lorce the piston upwardly, and at the limit ot' its upward movement the piston will have moved the rod 'to disengage the cams 37 from the rollers 34 to allow oi? the burner-valves to close and to shut otl' the fuel supply from the burners, with the exception of the last valve to operate which may be so arranged that it does not quite cles-e but leaves a small opening to allow a suii'icient quantity ot tuel pass to the burner tor the purpose ot keeping it a-light. lhe pressure ot the steam admitted to the cylinder 42 will be proportional to and, technically stated, Will be inversely proportional to the amount et steam passing through the re-heater and consequently the piston 4l will be depressed against the action ot' its spring in accordance With the steam pressure, thus opening one or more or the fuel-regulating valves in accordance with the amount ot steam passing through the re-heater.

The air supplied to the burners for the combustion ot the luel may be controlled in a similar manner. ton rod 45 extending from the lower tace otl the piston 41 can be connected to a bellerank lever 46, see Figures 5 and 6, Which in its turn is connected to a sliding rod ,47 similar to the rod and operating similarly through tappet-rods 48 connected with hit-and-miss air-regulators 49, one for each burner. rllhe movement ot the air-regulating devices can be operated in accordance with the opening ot the valves 32 and proportionately With the oil-supply thereto'. 1n Figure 5 the part 50 represents the barrel of the burner, and 5l the fuel supply conduit disposed therein. Y

It Will be therefore vappreciated that in accordance With the amount ot steam supplied to the turbine, in other words according to the pressure of the steam, more or less of the burners will operate for firing the re-heater. Thus, it' the load is cut oil the heat supplied to the re-heater will be cut down and vice versa. By this means damage to the re-h-eater by overheating of the parts, when only a small quantity et' steam or no steam is passing through the steam-tubes, is avoided. Y

1t is not essential to the invention that the feed-Water heater 30 be employed in the position shown in Figure 2, although it is par For example, a pispreferably so employed, and serves somewhat to cool the hot gases passing from the burners to the re-heating tubes, and protects them from a too fierce heat should the burners lbe operating too freely.

That I claim as my invention and desire yto secure by Letters Patent is :q

1. A regulating device for the reheater of a multiple expansion turbine comprising the combination with a plurality of fuel burners to heat the reheater, of a pressure-responsive regulator operating proportionately with the tru'bine-load in accordance with the pressure of the steam passing through the turbine, a fuel-control device for each burner, and means operatively connected With the regulator and with each of the control-devices, said means operating during a unidirectional movementto close or open in succession the control-devices of the burners as the turbineload falls or rises respectively, substantially as described. y

A regulating device for the reheater of a multiple expansion turbine comprising the combination With a plurality of fuel burners to heat the reheater, of a pressure-controlled regulator operated in accordance With the pressure of steam passing through the reheater, a fuel-control device for each burner, means operatively connected With the regulater and With each of the control-devices, said means operating during a. unidirectional movement to close or open in succession the control-devices of the burners as the turbineload rises or falls respectively, substantially as described.

regulating' device for the reheater of a multiple expansion turbine comprising the combination With a plurality of fuel burners :'or heating' the reheater, of a fuel-control device for the burners, a control-device for the air supplied to the burners, a pressureresponsive regulator operating proportionately With Vthe turbine-load in accordance with the pressure of the steam passing through the turbine, and means connecting the regulator With the fueland air-controlling devices to regulate the heating effect of the burners in accorda-nce with the turbineload, substantially as described.

l. Re-heating apparatus fora multiple expansion turbine comprising in combination a reheater chamber having Within it an air-heating device and a steam-chamber through Which steam can circulate, a plurality of fuel burners for heating the airheating device and the steam chamber, means to lead air from the air-heating device to the burners, a pressure-controlled regulator operated in accordance With the pressure of the steam passing' through the reheater, Va control-device for controlling the an'icunt of fuel supplied to the burners, and means operatively connecting said control-device with the regulator, substantially as described.

5. The combination with amulti-section steam turbine, a reheater for the steam as it passes from one stage to the neat, and heating means for the reheater, of a pressurecontrolled regulator comprising a piston-device in Which steam passing through the reheater is admitted to one face of the piston and spring pressure is applied to the other face in opposition to the steam pressure, and means connected With the regulator for automatically controlling the heat supplied to the reheater in accordance with the steam pressure operative on the piston, substantially as described.

6. A regulator device for the reheater between tvvo sections of a multiple expansion turbine, comprising in combination, a plurality of liquid-fuel burners for heating the reheater, a fuel control valve for each burner, a pressure-controlled regulator operated in accordance With the pressure of the steam passing between the sections, and a sliding member operatively connected with the regulator and With each of the control valves, said sliding member operating during a unidirectional movement to close or open in succession the valves of the burners as the steam pressure falls or rises respectively.

In testimony whereof I affix my signature.

ALBERrWILL'IAMiBOWERBANK. 

